Probably will be good make the sprite unit with similar features with exiting ones (MSX, CPC+, etc?) the easy can be ported existing sprite games.
I shouldn't be posting in such topics as I have no technical knowledge and no one likes when such wishlist starts but...
Please don't make the sprite hw work like the cpc+ one.
The sprite data are fixed so everytime you want to change animation frame you still need to copy data to the area.
I hope that the hw could work more like the c64 that the sprites can use the entire videoram and you specify which sprite matrix to use for given sprite. Can't remember how it was on the amiga... I think that there were registers that acted as 32bit data pointers for each sprite and sprites didn't have a fixed height but used a endsprite marker. But maybe I'm confusing something.
The sprite hw would have its own registers or could use only the free nick registers?
How would the sprites depend on the nick video mode chosen?
Or is it all depending on the sprite hw and "everything is possible"?